Evolution of the CoCo Virtual Drive System


MicroSD Drive Pak

  • Earliest all-in-one self-contained virtual drive system
  • Uses a 16K smart ROM that detects and employs numerous simultaneous drive systems
  • CoCoNet over 6551 ACIA
  • 115200 bps alternative serial port drives if 6551 device is unavailable
  • 4GB MicroSD card drives using unlimited partitioning scheme
  • Some known DOS-based software crashes due to programmers not calling DSKCON correctly, or attempt to use direct FDC code.



  • Earliest released floppy drive emulator
  • Requires a very close-by PC
  • Crashes due to programmers using hard-coded nonstandard calls to the DOS ROM
  • Crashes due to buggy server over unstable serial port circuitry combined with cable quality
  • Requires a bottle of Advil and much patience especially with the latest ridiculous DriveWire 4 by Aaron Wolfe.  And if the serial port doesn’t like 115200 bps very much, by all means push it to 230400 bps.
  • Not stable enough for serious applications, runs over noisy bitbanger link



  • Evolved on the MicroSD Drive Pak concept
  • Emulates the 1773 FDC controller using a cartridge and SD card
  • CoCo thinks the virtual disks are real FDC disks
  • Rare if any DOS software crashing


CoCo On A Chip

  • SD card virtual disk system
  • FDC circuitry, compatible with DOS and OS-9 without patches
  • WIFI virtual disk system (in development)
  • Bluetooth virtual disk system
  • FAT32 SD card support

Author: Roger Taylor